import { Mark, markInputRule, markPasteRule, mergeAttributes } from '@tiptap/core';

export interface ItalicOptions {
	/**
	 * HTML attributes to add to the italic element.
	 * @default {}
	 * @example { class: 'foo' }
	 */
	HTMLAttributes: Record<string, any>;
}

declare module '@tiptap/core' {
	interface Commands<ReturnType> {
		italic: {
			/**
			 * Set an italic mark
			 * @example editor.commands.setItalic()
			 */
			setItalic: () => ReturnType;
			/**
			 * Toggle an italic mark
			 * @example editor.commands.toggleItalic()
			 */
			toggleItalic: () => ReturnType;
			/**
			 * Unset an italic mark
			 * @example editor.commands.unsetItalic()
			 */
			unsetItalic: () => ReturnType;
		};
	}
}

/**
 * Matches an italic to a *italic* on input.
 */
export const starInputRegex = /(?:^|\s)(\*(?!\s+\*)((?:[^*]+))\*(?!\s+\*))$/;

/**
 * Matches an italic to a *italic* on paste.
 */
export const starPasteRegex = /(?:^|\s)(\*(?!\s+\*)((?:[^*]+))\*(?!\s+\*))/g;

/**
 * Matches an italic to a _italic_ on input.
 */
export const underscoreInputRegex = /(?:^|\s)(_(?!\s+_)((?:[^_]+))_(?!\s+_))$/;

/**
 * Matches an italic to a _italic_ on paste.
 */
export const underscorePasteRegex = /(?:^|\s)(_(?!\s+_)((?:[^_]+))_(?!\s+_))/g;

/**
 * This extension allows you to create italic text.
 * @see https://www.tiptap.dev/api/marks/italic
 */
export const Italic = Mark.create<ItalicOptions>({
	name: 'italic',

	addOptions() {
		return {
			HTMLAttributes: {}
		};
	},

	parseHTML() {
		return [
			{
				tag: 'i',
				getAttrs: (node) => (node as HTMLElement).style.fontStyle !== 'normal' && null
			},
			{
				style: 'font-style=italic'
			}
		];
	},

	renderHTML({ HTMLAttributes }) {
		return ['i', mergeAttributes(this.options.HTMLAttributes, HTMLAttributes), 0];
	},

	addCommands() {
		return {
			setItalic:
				() =>
				({ commands }) => {
					return commands.setMark(this.name);
				},
			toggleItalic:
				() =>
				({ commands }) => {
					return commands.toggleMark(this.name);
				},
			unsetItalic:
				() =>
				({ commands }) => {
					return commands.unsetMark(this.name);
				}
		};
	},

	addKeyboardShortcuts() {
		return {
			'Mod-i': () => this.editor.commands.toggleItalic(),
			'Mod-I': () => this.editor.commands.toggleItalic()
		};
	},

	addInputRules() {
		return [
			markInputRule({
				find: starInputRegex,
				type: this.type
			}),
			markInputRule({
				find: underscoreInputRegex,
				type: this.type
			})
		];
	},

	addPasteRules() {
		return [
			markPasteRule({
				find: starPasteRegex,
				type: this.type
			}),
			markPasteRule({
				find: underscorePasteRegex,
				type: this.type
			})
		];
	}
});